1. Field of the Invention
This invention relates to a moving object detecting and tracking apparatus which is suitable, particularly, for tracking a target object by, for example, moving a television camera in accordance with the movement of the target object.
2. Description of the Related Art
Heretofore, when tracking a target object by moving a television camera in accordance with the movement of the target object, the movement of the target object in an image photographed by the television camera is first detected. Block matching is a detection method generally adopted for this movement detection. In block matching, an image inside a frame is divided into a plurality of blocks, and correlative calculation is performed on the target block in relation to the next frame in which it is continuously followed up in terms of time to determine its movement on the basis of a minimum-error block regarded as the corresponding block.
In movement detection by this block matching, matching is effected without isolating the target object from other objects or the background, so that the final judgment is made based on a statistic quantity. That is, if the correct correspondence is not taken, movement determination can be effected by selecting a block involving the minimum amount of errors.
However, in the above-described movement detection method based on block matching, the correlative calculation, which is performed on the target block and the next frame continuously following the same in terms of time, involves a great amount of calculation. Further, there is a problem that a patternized object movement cannot be detected.
In addition, since it only consists of a simple block matching in which movement detection is effected on the basis of the correlation between the target block and the next frame continuously following the same in terms of time, the method cannot cope with any change in the size of the object, the target object not being specified. Thus, even when the object has disappeared from the visual field, the position of minimum correlative calculation will be output as the corresponding block, resulting in an erroneous movement detection.